Contactless systems (magnetic field communication systems) that use a contactless integrated circuit (IC) card are known. Such contactless systems are, for example, used as electronic tickets and electronic money. In a contactless communication system, an antenna included in the contactless IC card receives a magnetic field signal transmitted by a magnetic field antenna in a reader/writer (R/W) device and transmits predetermined information in response as a magnetic field signal to the R/W device. Communication is thus established between the contactless IC card and the R/W device. Patent literature (PTL) 1, for example, discloses an example of a contactless communication system.
A transmission system that uses a dielectric as a transmission medium to transmit a high-frequency signal or high-frequency power is also known. In particular, such a transmission system is referred to as a human body communication system, for example, when the dielectric is a human body. In the human body communication system, communication with a transmission device is established when the human body touches an electrode of the transmission device, whereas communication with the transmission device is not established when the human body is not touching an electrode of the transmission device. PTL 2 and PTL 3, for example, disclose examples of a human body communication system.